Intra-Aortic Oxygen Distribution during Veno-Arterial Bypass (VAB) without Oxygenation in Circulatory Assist

摘要

Right atrium-femoral artery VAB without oxygenation was performed in 7 dogs at 3 different bypass ratios, 15%, 30%, and 45%. Respiration and cardiac output were controlled. Precise intra-aortic distributions of PO2 and O2 saturation were determined by means of a PO2 catheter probe and an oxygen analyzer.The following was concluded: 1) The blood pumped from dog heart produced a narrow "mixing zone" in the mid-aorta with the blood pumped from VAB. The area of the "mixing zone" was in the distal half between renal artery and bifurcation at 15% bypass ratio, in the proximal half between renal artery and bifurcation at 30% bypass ratio, and from celiac artery to below renal artery at 45% bypass ratio. It shifted proximally as the bypass ratio increased.2) In order to supply necessary oxygen to abdominal viscera, it is recommended that the bypass flow should not exceed 30% of the baseline cardiac output.